Admin: expose PCU Groups (+ other fields) in CreateDatabase and add ListPcuGroups method

[sl-at-ibm]

This is a c# counterpart to a similar astrapy issue, plus this extension to create_database.

Specs

CreateDatabase (and async) new fields + validation of pcu group id if passed to CreateDatabase + classes to describe pcu groups + method to retrieve pcu groups.

CreateDatabase

The CreateDatabaseOptions gets new optional fields which map to payload fields:

• Tier, serializes as tier, defaults to "serverless"
• CapacityUnits, serializes as capacityUnits, defaults to 1
• DBType, serializes as dbType, defaults to "vector"
• PCUGroupID, serializes as pcuGroupUUID, absent by default (i.e. null and therefore not serialized to payload)

Validation

If a non-null PCUGroupId is passed in the CreateDatabaseOptions parameter to CreateDatabase, a pre-check on the client side is done to ensure the PCU Group exists. If not, an Error is raised right away and no create-db request is fired.

(actually two different errors: (1) pcu group does not exist, (2) pcu group is in a different cloudprovider/region setting).

Listing PCU Groups

AstraDatabasesAdmin must offer a method to list the PCU Groups for the current org, following the corresponding POST /v2/pcu/actions/get DevOps API endpoint.

According to the yellow doc, clients may add a filtering: this requires a ListPCUGroupsOptions: CommandOptions
(if passed, both CloudProvider and Region are required): so,

public List<PCUGroup> ListPCUGroups(ListPCUGroupsOptions options = null)
public Task<List<PCUGroup>> ListPCUGroupsAsync(ListPCUGroupsOptions options = null)

PCU descriptor classes

all must come with unmarshaling capabilities and tolerating missing/null fields in the responses. As the only one directly mentioned in the above methods, it is ok to just have the three of them into a single, src/DataStax.AstraDB.DataApi/Core/PCUGroup.cs.

Below is a stub - there is additional care involved, such as:

• missing fields (strings, subobjects, instances of AstraDatabaseCloudProvider)
• parsing of DateTime
• unmarshaling into the cloud provider enum (like is done elsewhere)
• missing integers unmarshal as zeroes

public class PCUGroup
{
    [JsonPropertyName("uuid")]
    public string Id { get; set; }

    [JsonPropertyName("orgId")]
    public string OrgId { get; set; }

    [JsonPropertyName("title")]
    public string Title { get; set; }

    [JsonPropertyName("cloudProvider")]
    public AstraDatabaseCloudProvider CloudProvider { get; set; }

    [JsonPropertyName("region")]
    public string Region { get; set; }

    [JsonPropertyName("instanceType")]
    public string InstanceType { get; set; }

    [JsonPropertyName("pcuType")]
    public PCUType? PCUType { get; set; }

    [JsonPropertyName("provisionType")]
    public string ProvisionType { get; set; }

    [JsonPropertyName("min")]
    public int Min { get; set; }

    [JsonPropertyName("max")]
    public int Max { get; set; }

    [JsonPropertyName("reserved")]
    public int Reserved { get; set; }

    [JsonPropertyName("description")]
    public string Description { get; set; }

    [JsonPropertyName("createdAt")]
    public DateTime CreatedAt { get; set; }

    [JsonPropertyName("updatedAt")]
    public DateTime UpdatedAt { get; set; }

    [JsonPropertyName("createdBy")]
    public string CreatedBy { get; set; }

    [JsonPropertyName("updatedBy")]
    public string UpdatedBy { get; set; }

    [JsonPropertyName("status")]
    public string Status { get; set; }
}

public class PCUType
{
    [JsonPropertyName("type")]
    public string type { get; set; }

    [JsonPropertyName("region")]
    public string region { get; set; }

    [JsonPropertyName("provider")]
    public AstraDatabaseCloudProvider CloudProvider { get; set; }

    [JsonPropertyName("details")]
    public PCUTypeDetails Details { get; set; }
}

public class PCUTypeDetails
{
    [JsonPropertyName("vCPU")]
    public int VCpu { get; set; }

    [JsonPropertyName("memory")]
    public string Memory { get; set; }

    [JsonPropertyName("disk_cache")]
    public string DiskCache { get; set; }
}